The present embodiments relate to tunneling a real-time protocol (RTP) packet. During a typical video conference, an H.221 frame may be used to transmit portions of an RTP packet between an originating gateway and a terminating gateway. Before transmitting the RTP packet, the originating gateway removes the RTP header and RFC-specific sub-header. When performing the RTP de-packetization, the information in the RTP sub-headers and fragmentation boundaries, specified in the IETF RFC for each of the video codecs, are lost. Once the RTP packet is de-packetized, only the video bits from the RTP packet are copied into the sub-channels of the H.221 frame. Upon arrival at the terminating gateway, the fragmentation boundaries and RTP sub-headers are re-determined. The process of re-determining the RTP fragmentation boundaries and RTP sub-headers is a computationally intensive task. In addition, calculation of the boundaries and RTP sub-headers is based on defined specifications. As these specifications are modified, the conferencing system must be updated to accommodate the modified specifications.